Welcome back.
Any laptop IDE hard drive will work. It's important you get the "IDE" part right, because since you were last here, they've started coming out with laptop SATA drives, which won't work on the empeg.
Since you were last here, the available hard disks have also gotten bigger, big enough to cause issues with the original firmware, and now upgrading your hard disks to something bigger than 60gb involves using custom-modified versions of the builder image and player firmware that supports large hard disks.
But before assuming that it's the hard disk crapping out, check
here and go through all those diagnostic steps to make sure that you're not having an easily-repairable problem unrelated to the disk itself.
When you're ready to put new disks in the player, the entire procedure is
here.